DI It does depend on what OS you are running. I'm running 9.1 so I'm downloading via the link on this page. (I tried to search the Apple site for the link I needed but, as per usual, couldn't find anything and googling brought me here which sent me back to the right spot on the Apple site. Bit funny that you have to go outside Apple to get a decent link to resources inside Apple!)
Anyways... a 2gig iMac sounds oldish so I'm assuming that you are not running System X. If that is the case then CarbonLib 1.6, accessible via the link on this page, should do the trick. It's for System 8.6-9.x. Download it, unstuff it and drag the icon into your extensions file. (Backup any CarbonLib that is already there just in case you have to go back to the old version for any reason.) Hope this helps.
(Version 1.6.1)